Characteristics of the transport and vertical structure of aerosols during ABC-EAREX2005

In this study, we investigate the physio-chemical and optical properties of Asian spring continental outflow and its relation to synoptic transport patterns. Ground-based highly time-resolved measurements of aerosol chemical and physical properties, and lidar measurements of aerosol vertical distributions at Gosan, Korea during ABC-EAREX2005 have been analyzed. Two selected cases, based on PM10 and PM2.5 mass concentrations, indicate that pollution-dominant airmass preceded by the appearance of a major mineral dust plume with about 12 h time-lag. At the ground level, pollution aerosol components (NO3−, SO42−, and NH4+) showed distinct peaks first and the enhancement of soil components (Ca2+) appeared approximately 12 h later. Although lidar measurements reveal that spherical pollution particles were observed near the surface prior to a major plume of non-spherical mineral dust, elevated dust layers were simultaneously observed in the free troposphere overlying the ground-level pollution plume. Chemical transport model simulations of the horizontal distributions of dust and sulfate aerosols illustrate well the pollution plume preceding the dust-laden airmass. Backward trajectory and NCAR/PSU MM5 analysis show that the preceding pollution plume and following dust plume were consecutively transported under fast northwesterly/northerly winds formed between anti-cyclonic and cyclonic flows at the ground level.